/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.flink.runtime.topology;

/**
 * A pipelined region is a set of vertices connected via pipelined data
 * exchanges.
 *
 * @param <VID> the type of the vertex ids
 * @param <RID> the type of the result ids
 * @param <V> the type of the vertices
 * @param <R> the type of the result
 */
public interface PipelinedRegion<VID extends VertexID, RID extends ResultID,
	V extends Vertex<VID, RID, V, R>, R extends Result<VID, RID, V, R>> {

	/**
	 * Returns vertices that are in this pipelined region.
	 *
	 * @return Iterable over all vertices in this pipelined region
	 */
	Iterable<? extends V> getVertices();

	/**
	 * Returns the vertex with the specified vertex id.
	 *
	 * @param vertexId the vertex id used to look up the vertex
	 * @return the vertex with the specified id
	 * @throws IllegalArgumentException if there is no vertex in this pipelined
	 *                                  region with the specified vertex id
	 */
	V getVertex(VID vertexId);

	/**
	 * Returns the results that this pipelined region consumes.
	 *
	 * @return Iterable over all consumed results
	 */
	Iterable<? extends R> getConsumedResults();
}
